Recently, semiconductor devices such as a LSI or the like have been required to have higher density in order to meet requirements for reducing the mounting space or for improving the processing rate. As an example of a technology that achieves the high density, there has been known a multilayer wiring technology of manufacturing a multilayer substrate, such as a three-dimensional LSI or the like, by stacking multiple wiring substrates.
According to the multilayer wiring technology, a TSV (Through Silicon Via), which penetrates the wiring substrates and in which a conductive material such as copper (Cu) is buried, is typically formed in the wiring substrate in order to obtain electrical connection between the wiring substrates. As an example of a technology for forming the TSV in which a conductive material is buried, there has been known an electroless plating method.
In case of forming a metal film by the electroless plating, it is required to improve adhesivity between a base and the metal layer. For the purpose, conventionally, a self-assembled monolayer (SAM) is formed on the base by using a coupling agent such as a silane coupling agent or a titanium coupling agent, and a metal catalytic particle such as a palladium particle is provided on the base with the self-assembled monolayer therebetween (see, for example, Patent Document 1).
In general, since a main component of the titanium coupling agent is TiOx, a performance of adsorption of the metal catalytic particle is superior. For this reason, adhesivity of the metal film can be improved by forming a titanium coupling agent-based coupling layer with the titanium coupling agent.
As such, conventionally, the metal catalytic particle is coupled onto the titanium coupling agent-based coupling layer, and then, the metal film is formed by the electroless plating with the metal catalytic particle. However, there may be a case where the metal catalytic particle is not sufficiently coupled to the coupling layer due to a surface shape of the coupling layer. In this case, even if the metal film is formed by the electroless plating with the metal catalytic particle, it is difficult to securely form the metal film with a high precision.    Patent Document 1: Japanese Patent Laid-open Publication No. 2002-302773